Rotor, motor, and electric power steering device

Abstract

A rotor includes a shaft, a rotor core, at least one magnet, and at least one fixing portion. The shaft extends in an axial direction. The rotor core includes laminations, and at least one caulking portion. The laminations are stacked in the axial direction. The at least one caulking portion is located at a radial-directional inner side of the at least one magnet to caulk the laminations to each other. The at least one magnet is embedded in the rotor core. The at least one fixing portion fixes at least portions of outer peripheral edges of the laminations to each other.

The invention claimed is: 
     
       1. A rotor comprising:
 a shaft extending in an axial direction; 
 a rotor core including a plurality of laminations stacked in the axial direction, and at least one caulking portion disposed at a radial-directional inner side of at least one magnet to caulk the plurality of laminations to each other; 
 the at least one magnet embedded in the rotor core; and 
 at least one fixing portion fixing at least portions of outer peripheral edges of the plurality of laminations to each other; wherein 
 the at least one caulking portion, the at least one magnet, and the at least one fixing portion are linearly arranged in a direction. 
 
     
     
       2. The rotor of  claim 1 , wherein the at least one fixing portion is a welded portion at which outer peripheral edges of the laminations are welded to each other. 
     
     
       3. The rotor of  claim 1 , wherein the plurality of laminations define at least one lamination group, and the at least one caulking portion and the at least one fixing portion are provided for each lamination group. 
     
     
       4. The rotor of  claim 3 , wherein the at least one lamination group defines a plurality of lamination groups, and the plurality of lamination groups are deviated from each other in a circumferential direction. 
     
     
       5. The rotor of  claim 1 , wherein the rotor core includes a plurality of convexities protruding outward in the radial direction and disposed in the circumferential direction, a number of the at least one magnet and a number of the at least one fixing portion are the same as a number of the plurality of convexities, and the at least one fixing portion is disposed at a vertex of one of the plurality of convexities. 
     
     
       6. The rotor of  claim 5 , wherein the at least one lamination group defines a plurality of lamination groups and circumferential positions of each of the plurality of convexities in each of the plurality of lamination groups, are different from each other. 
     
     
       7. The rotor of  claim 1 , wherein the rotor core includes a plurality of lightening holes penetrating the rotor core in the axial direction, a number of the at least one caulking portion is the same as a number of the plurality of lightening holes, and the plurality of lightening holes and the at least one caulking portion are alternately disposed in the circumferential direction. 
     
     
       8. The rotor of  claim 7 , wherein each of the plurality of lightening holes in each of the plurality of lamination groups are in communication with each other. 
     
     
       9. The rotor of  claim 1 , wherein a number of the at least one magnet, a number of the at least one caulking portion, and a number of the at least one fixing portion are the same. 
     
     
       10. A motor comprising:
 the rotor of  claim 1 ; and 
 a stator facing the rotor in a radial direction and including a plurality of coils. 
 
     
     
       11. An electrical power steering device comprising the motor of  claim 10 , a steering shaft, and an axle.